Operating a head-up display with objects that can be shown located outside a field of view

ABSTRACT

A head-up display and techniques for operating a head-up display for a motor vehicle. An assignment is obtained of at least one virtual object that can be displayed to a part of the environment. The head-up display may be operated in a normal display mode when the object assigned to the part of the environment is within a field of view for the head-up display. The head-up display is then operated in an alternative display mode when the object assigned to the part of the environment is not, or not entirely, contained within the field of view for the head-up display, wherein a virtual display is generated in the alternative display mode.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority to German Patent Application No.DE 10 2020 212 412.4, to Kunze, et al., filed Sep. 30, 2020, thecontents of which is incorporated by reference in its entirety herein.

FIELD OF TECHNOLOGY

The present disclosure relates to a method for operating a head-updisplay, wherein the head-up display is configured for a motor vehicle.The motor vehicle can be an automobile or a truck, for example.

BACKGROUND

Head-up displays (HUDs) for showing virtual objects, or, in other words,virtual content in a driver's field of view is known in the automotiveindustry. From the perspective of the driver, the virtual objects aresuperimposed on the environment. These objects can be displayed in theknown manner on the inside of a windscreen, e.g., by projecting theobjects thereon. Separate projection surfaces, and transparentprojection screens in particular, on which the objects are projected,are also known. The technological background for head-up displays ingeneral is disclosed, e.g., in US 2019/0043392 A1 and FR 3 060 774 A1.

A head-up display with expanded reality is known from DE 10 2019 206 490B3. Graphics are shown thereon as a function of the distance of themotor vehicle to an object in the environment of the motor vehicle.

To be able to show the objects as reliably as possible, and plan in ananticipatory manner, it is known to regard or generate virtual models ofa motor vehicle's environment.

Virtual objects that can be shown are assigned to specific parts of avehicle's environment, such that they are positioned in the model of theenvironment. As soon as these objects, or the part of the environment towhich they are assigned, enter the field of view of the head-up display,or overlap such a field of view, or overlay it, the objects can beshown. From the perspective of the driver, the objects are then shown inthe correct position, and/or anchored to a location within theenvironment.

Objects can also be assigned to real regions in the environment (andmodeled with regard to a model of the environment, for example), andthey can also be depicted in relation to the location and/or inperspective, and in particular in three dimensions. This is typical forexpanded reality head-up displays. Such objects can also be referred toas contact-analog objects or display elements. This can relate tohighlighting real objects in the environment (e.g., by framing them),such as traffic signs. These objects can also be navigationinstructions, e.g., turning arrows, or arrows indicating the directionof travel in general, which are assigned to specific roadways orintersections, for example. General instructions that are notnecessarily assigned to a specific object in the environment, but onlyrefer to a certain part of the environment, can also be shown. These canbe warnings such as a symbol for icy conditions or speed limits, forexample. This information can be assigned to specific parts of theenvironment in an environment model, and be displayed when the motorvehicle enters this region and/or the part of the environment is withinthe field of view.

It has been realized that this approach does not yet succeed in thedesired manner at present. For one thing, the display thereof within thefield of view may be late from the perspective of the driver if it firsttakes place when the object in question and/or the associated part ofthe environment lies directly within the field of view of the head-updisplay. It may also be the case that a driver displaces the field ofview such that what are consider to be important objects (e.g.,navigation instructions) that are linked to a real location in theenvironment (e.g., the center of an intersection) do not overlap thefield of view at all while driving. In this case, the driver mayoverlook them entirely. There are various ways for a driver to adjust afield of view in a head-up display (e.g., directly or indirectly byvarying the so-called “EyeBox”) that are known in the prior art.

There is therefore a desire for a more reliable displaying of objects ina head-up display, in particular when objects are assigned to regions ofthe vehicle's environment.

SUMMARY

In general, a head-up display is disclosed to be operated in accordancewith different operating modes. In a normal display mode, the head-updisplay can be operating in the conventional manner, and then show anobject assigned to a part of the environment when this specific part ofthe environment lies within a field of view of the head-up display. Theobject is preferably depicted three dimensionally and/or in perspective.In particular, the object is preferably superimposed on the part of theenvironment it relates to from the driver's perspective, thus appearingas part of the environment in the upcoming direction of travel. Thesedepictions are known in theory, and can take place using so-calledaugmented reality head-up displays of the type described above. Thehead-up display presented herein can therefore be such an expandedreality head-up display and/or be configured in general for showingexpanded reality objects, e.g., through a perspective and/orthree-dimensional depiction and/or location-specific display with acorresponding location-specific superimposing thereof on reality.

The present disclosure also provides that an object assigned to a partof the environment is displayed, or used to activate the normal displaymode and/or alternative display mode. As such, numerous objects that canbe displayed in theory may be detected in a model of the environment,e.g., depending on a route selected by a driver or a route that appearsto be probable. Only the object that is anticipated to be the next oneto be shown, e.g., the object closest to the motor vehicle, or belongingto a part of the environment that is closest to the motor vehicle, isthen preferably regarded. As a result, it is possible to reliablydetermine which of the objects that can be shown should be regarded forselecting the normal display mode or the alternative display mode, i.e.,that should be decisive for which of these modes is to be activated. Thedisplay can still show objects and information that are notlocation-specific independently thereof, which are not assigned tospecific parts of the environment, for example.

In some examples, technologies and techniques are disclosed foroperating an expanded-reality head-up display for a motor vehicle thatincludes obtaining an assignment of a virtual object that can bedisplayed to a part of the environment; operating the head-up display ina normal display mode when the object assigned to the part of theenvironment is located in a field of view for the head-up display;operating the head-up display in an alternative display mode when theobject assigned to the part of the environment is not, or not entirely,located in a field of view for the head-up display, wherein a virtualdisplay is generated in the alternative display mode.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention shall be explained below on thebasis of the following schematic drawings. Therein:

FIG. 1 shows a motor vehicle comprising a head-up display according toan exemplary embodiment with which a method according to an exemplaryembodiment is executed while motor vehicle approaches an intersection;

FIG. 1 a shows a flow chart according to the method executed in FIG. 1according to some aspects of the present disclosure;

FIGS. 2 and 3 each show exemplary views that can be generated with themethod in FIG. 1 a according to some aspects of the present disclosure;

FIG. 4 shows a view that can be generated with the method in FIG. 1 a ,when an object assigned to a part of the environment is only located inpart in a field of view according to some aspects of the presentdisclosure;

FIGS. 5-7 show views of a virtual object in a field of view in variousoperating conditions and when satisfying a defined size criterion forthe object in relation to the field of view according to some aspects ofthe present disclosure; and

FIG. 8 shows a schematic view of a field of view analogous to that inFIGS. 2 to 7 , when the vehicle is temporarily elevated according tosome aspects of the present disclosure.

DETAILED DESCRIPTION

In some examples, numerous virtual objects that can be displayed can beassigned to a part of the environment, but they are then preferablyassigned to individual parts of the environment. As explained herein,preferably only one of these objects is then regarded, in particular theobject in theory that is to be displayed next (e.g., the next object tobe displayed next along a route for the motor vehicle), for choosingbetween the various display modes.

Measures may also be determined for determining whether or not theobject overlaps the field of view (or is located therein). One of theaforementioned display modes can then be selected according to theresults of these measures. The assigning of objects to parts of theenvironment can also be part of the process.

In some examples, assigning virtual objects to part of the environmentcan take place virtually, e.g., with a corresponding placement in adatabase, and/or associating or assigning coordinates in the environmentto the virtual object. In particular, the virtual object can be placedvirtually in or on the part of the environment, e.g., in a model of theenvironment. This can also mean that the object can be assignedcorresponding coordinates in the environment in the model of theenvironment or its coordinate system. In other words, the object can beclearly located and/or positioned in the model of the environmentthrough a corresponding assignment thereto.

In some examples, the part of the environment can also be purelyvirtual. It can thus correspond to an area in the model of theenvironment, including a corresponding number of points or coordinates.It can be explicitly assigned to a real part of the environment, and/orcorrespond thereto.

A position of the motor vehicle can be determined in the model of theenvironment, for example, on the basis of positioning systems, such as aGPS-based positioning system. Determination of the orientation of afield of view in a head-up display, for example, in a motor vehiclecoordinate system, is also known. This field of view can be a field,area, or region in general in which objects can be shown with thehead-up display, and projected therein in particular. The position ofthe field of view within the motor vehicle can be determined on thebasis of where the head-up display is installed in the motor vehicle,and/or on the basis of settings of optical components in the head-updisplay in particular, as long as can be varied by the driver, e.g., forvarying an EyeBox.

The position of the field of view can then be determined within themodel of the environment from a known relative location of the motorvehicle (and in particular its coordinate system) to the environment(such as a global coordinate system in a model of the environment), andin particular, with which parts of the environment it overlaps and/orwhich parts of the environment are currently within the field of view(i.e. overlapping, covering and/or detected in the field of viewtherewith). Current vehicle parameters can be drawn on for this, e.g.,suspension settings that have an effect on the vertical position of thedriver's compartment and/or the head-up display in relation to theroadway).

It is also possible to determine in this manner that a position of thepart of the environment and/or objects in the model of the environmentassigned thereto, is known, as well as the position of a field of viewand/or the part of the environment that is currently detected in thefield of view. As a result, it is possible to check whether or not anobject this is to be currently shown, or the part of the environmentassigned to this object, is located within the field of view.

In some examples, the part of the environment can be punctiform. It candefine the center of a real object that is to be framed, for example,and/or serve as a type of anchor for showing instructions. The objectcan extend beyond a corresponding punctiform (or two-dimensional) partof the environment, and have a greater two-dimensional expansion. Inthis regard, it is checked whether or not the object is located entirelywithin the field of view when it is positioned on the part of theenvironment with its two-dimensional (or three-dimensional) extension.In other words, a detection of an object positioned on or in theenvironment is checked by the field of view.

To operate the head-up display in the specified manner, it can include acontrol unit in general, or be connected to such. The control unit caninclude at least one processor and/or at least one memory. Programinstructions can be stored in the memory with which the processor causesthe control unit to execute any of the steps or measures specifiedherein. By way of example, the control unit can obtain informationrelating to an assignment of at least one virtual object to a part ofthe environment after entering a desired route by querying a database,or from an external server. Alternatively, it can also make thisassignment itself. The control unit can subsequently determine theposition of a field of view in the head-up display, e.g., in the(global) coordinate system for a model of the environment (also referredto as an environment model). The (complete) imaging of the object in thefield of view can subsequently be checked, and the appropriate displaymode can then be selected on the basis thereof. The control unit cansubsequently control the head-up display in the manner known per se togenerate desired virtual displays.

In general, the virtual display in the alternative display mode candiffer from a display of the object that would take place if this objectwere in the field of view. In particular, the display can then takeplace at a fixed location or region within the field of view, and/or thedisplay can take place independently of the movement of the field ofview in relation to the environment or the object, at least as long asit is not located in the field of view. In other words, in thealternative display mode, the display can take place in a fixed locationwithin the field of view, which is not the case in the normal displaymode. In the normal display mode, the position of the content that isdisplayed (in particular the object) also varies with the movement ofthe field of view in relation to the environment. The object, or itsdisplay, is preferably anchored to the part of the environment in thiscase, or can be regarded as having a fixed location within theenvironment. The opposite may be the case in the alternative displaymode (fixed in place in the field of view, such that it moves inrelation to the environment). Furthermore, objects can be displayed at aconstant size in the alternative display mode, without relating todistances within the environment. In the normal display mode, the sizedof these objects can be displayed in relation to their distances.

In some examples, the display is generated in the alternative displaymode taking the type and/or content of the object into account. Inparticular, the display can relate to a similar or identical object thatis assigned to the part of the environment. Optionally, this objectassigned to the part of the environment can be scaled in size. The sizealso does not have to depend on the distance thereto. A type of objectcan be understood to be whether it is a warning, a traffic sign, inparticular a speed limit sign, or navigation instructions. There arealso different types or classifications of navigation instructionsand/or warnings. In general, this variant also provides that, althoughthe object is not currently within the field of view, an at leastcomparable (e.g., containing the same content) or an identical object isdisplayed.

A virtual display may be configured with a fixed location within thefield of view in the alternative display mode, and can take place inparticular at a fixed position or within a fixed area. By way ofexample, this can be at a (vertically) upper border of the field of viewfrom the driver's perspective, or a (vertically) upper edge thereof.Displaying in this region (potentially in a special color or withspecial graphics) can be understood by the driver as a clear indicationthat the object is assigned to a part of the environment not yetcurrently within the field of view. In particular, the driver canunderstand this to mean that this refers to an upcoming object or anupcoming part of the environment that the object relates to. A displaycan also take place at the lower border or edge of the field of view, orsome other arbitrary position within the field of view. The displaypreferably takes place in the middle, or at a horizontally constantposition.

In general, one development provides that in the alternative displaymode, the display is generated taking a position of the object assignedto the part of the environment in relation to the field of view intoaccount. The relative position can be determined and/or defined in the(global) coordinate system for a model of the environment. By way ofexample, the display can take place near the edge or border of the fieldof view that is closest to the object in question (from the perspectiveof the field of view).

In some examples, a direction can be determined in this context as therelative location (or on the basis thereof) in which the object isdisplaced in relation to the field of view. The direction can beembodied, for example, by a two- or three-dimensional vector. In thealternative display mode, the display can be displaced in relation tothe center of the field of view, in substantially the same direction. Ingeneral, the display can take place analogously to, or taking intoaccount, the aforementioned relative location.

This can relate to the case in particular in which the relative positionis a position above or below, or to the right or left, of the field ofview, which are each exemplary directions of the aforementioned type.The display can then likewise take place such that a content displayedabove, below, left, or right (from the perspective of the driver) isdisplaced in relation to the center of the field of view.

One advantage is that when the object assigned to the part of theenvironment does enter the field of view, and the display is switched tothe normal display mode, a more natural transition takes place in thedisplay from the perspective of the driver. By way of example, thistransition is not abrupt, and/or it can take place smoothly. This isfacilitated in the present case in that the object displayed in thealternative display mode (or the display taking place in general)already takes place with an awareness of the relative location of theobject in the environment, and is preferably at the closest edge orcorresponding border of the display. From the perspective of the driver,an object can first be displayed in the alternative display mode, whichthen begins to shift when the object located in the environment actuallymoves into the field of view, in accordance with the location inrelation to this object, and begins to move successively toward themiddle of the field of view. Instead of a field of view, a region ofvision can also be referred to here.

The display may take place at or near an edge region of the field ofview in a generally preferred variant in the alternative display mode.The edge region can be selected on the basis of the relative position ofthe object to the field of view explained above. Alternatively, this canbe a fixed edge region (in particular the upper or lower edge).

In one example, when the object (assigned to the part of theenvironment) (e.g., in an initial display in particular) covers (orspans or overlaps) a portion of the field of view to a predeterminedminimum extent, this object is then also at least partially displayedwhen it is not entirely within the field of view. In other words, thealternative display mode does not need to be activated. Alternatively,it can first be activated when the object is actually entirely outsidethe field of view. The object can be transparent, such that it coversthe field of view, but preferably does not conceal it entirely. In otherwords, the object and the field of view can have a dimension along acommon axis (e.g., horizontally) and the size of the object cancorrespond to a minimum portion of the size of the field of view.

In this variant, at least those parts of the object can be displayed,depending on a corresponding minimum size of the object, that currentlyoverlap the field of view, or are located therein. The basis for this isthat the object, due to its size, can be sufficiently noticeable fromthe driver's perspective, and by way of example, a partial displaythereof provides the driver with enough information for it to be clearlyidentified. In this manner, unnecessary changes in the display mode thatcould potentially irritate the driver are avoided.

Alternatively or additionally, the display can move in relation to thefield of view in the alternative display mode, when a temporary changetakes place in the field of view in relation to the environment (e.g.,along a vertical axis and/or due to a change in elevation of the motorvehicle). By way of example, the display within an environmentcoordinate system may remain at least temporarily in the same location,e.g., along at least two coordinate axes, in this case. This locationcan correspond to the location of the display in the correspondingcoordinate system, before this temporary change takes place. Thedisplayed content can therefore be fixed in place in the environment,decoupled from the field of view, such that the field of view moves inrelation thereto. As a result, the object may at least partially moveout of the field of view, but then resume its original position withinthe field of view when the vertical movement subsides. The object isthen fixed in place within the field of view, or its coordinate systemat the latest when this takes place, and/or it is no longer fixed inplace within the environment or a global coordinate system. This displayvariant may be intuitive from the driver's perspective, because itreflects or absorbs the relative movement (in particular an impact-likeor abrupt pitching).

In general, a temporary change in the relative location (between thefield of view and the environment) can be detected on the basis ofmeasurements by at least one acceleration sensor in the motor vehicle inthe above variants. In other words, the fact that this change in therelative location is merely temporary can be determined on the basis ofcorresponding measurement values. If, for example, the measurements ofthe acceleration sensor exceed a predetermined minimum, it can beconcluded that such an abrupt change is the result of driving over anobstacle. Temporal changes in the measurement values can also beregarded in order to identify vibrational patterns, or movement patternsin general, resulting from driving over elevated obstacles, such asbumps or depressions. Appropriate comparison sequences or patterns canbe stored for this.

In some examples, the present disclosure also relates to a head-updisplay for a motor vehicle, which is designed to obtain a virtualobject assigned to a (vehicle's) environment (e.g. from an externalcomputer, e.g., a server and/or by accessing a memory or database,and/or through an independent determination or provision of such anassignment), and which can also be operated in a normal display modewhen the object assigned to the environment (and positioned therein, forexample) is located in a field of view for the head-up display, andwhich can be operated in an alternative display mode when the objectassigned to the part of the environment is not, or at least notentirely, located within a field of view for the head-up display,wherein at least one virtual display can be generated in the alternativedisplay mode.

The head up display can include any of variants or developmentsdescribed above, for example, by including an aforementioned processorand/or memory. It can be configured in general to execute methodsaccording to any of the variants specified herein. All of the aboveembodiments for and developments of method features can likewise relateto the features of the head-up display of the same descriptions, or beprovided therein.

A driving situation for a vehicle 10 is shown in FIG. 1 , where thevehicle approaches an intersection 14 along a roadway 12 in accordancewith the movement arrow B. This illustration can correspond to a realdriving situation. It can also be modeled in a model of the environment.The model of the environment is preferably abstract, and only definesselected properties of the environment in the indicated global(environment) coordinate system 16.

A position of the vehicle 10 and preferably a (vehicle) coordinatesystem 18 connected to the vehicle can be determined in this globalcoordinate system 16. Coordinates defined in the vehicle coordinatesystem 18 can be transformed into global coordinates in the globalcoordinate system 16 in a manner known per se. One example ofcoordinates defined in the vehicle coordinate system 18 are thecoordinates for a head-up display 20 (also referred to below as an HUD20). Coordinates for a field of view 21 can likewise be determined inthe vehicle coordinate system 18. As indicated above, these can also bepositioned in a variable manner by shifting the HUD 20. In particular,vertical and horizontal orientations of the field of view 21 can bedefined by this means from the perspective of the vehicle 10 or a drivertherein. The terms vertical and horizontal can refer to correspondingvertical and horizontal spatial directions, wherein the vertical axiscan correspond to an axis along which the force of gravity acts. Thehorizontal axis can be orthogonal to the vertical axis. An optionaldepth axis can run along or parallel to the longitudinal axis of thevehicle.

A center MK of the intersection 14 may be defined in the globalcoordinate system 16 by way of example, and more precisely, itscoordinates are defined therein. This center MK of the intersection isassigned a visual or graphic navigation instruction 22 (depicted by wayof example as three successive arrows, see the following figures). Thisassignment means that the position of the navigation instruction 22,which is a virtual object in this example, defined in the globalcoordinate system 16. The display of this navigation instruction 22should take place in accordance with the principles of known augmentedreality HUDs from the perspective of the driver, such that it is locatedat the center MK of the intersection, or optically coincides therewith.The position of this center MK of the intersection can be determined inthe field of view 21 for this (e.g., by comparing the global coordinatesthereof), and can be shown at the corresponding position in the field ofview 21, and the navigation instruction 22 can be optionally displayedin a perspective manner and/or such that its size is adaptedaccordingly.

Situations may occur, however, due to the circumstances described above,in which the navigation instruction 22 is not in the field of view 21when it is positioned virtually at the center MK of the intersection,despite driving toward the intersection 14, or at least does not fullyoverlap this center MK. For this reason, the proposed exemplaryembodiment provides for an alternative display mode, which is describedbelow.

The general operation of the HUD 20 shall be explained separately, onceagain, in reference to FIG. 1 a . Information relating to an assignmentof the object to be displayed in the form of a navigation instruction 22to a part of the environment (the center MK of the intersection in thisexample) is obtained in step S1. Alternatively, this assignment can becarried out actively in step S1, e.g., by the HUD 20, or a control unitthereof, not shown separately. The assignment includes defining orobtaining the coordinates for the navigation instruction 22 in theglobal coordinate system 16.

In some examples, a position of the field of view 21 may be determined,continuously and/or repeatedly, in the global coordinate system 16 instep S2. It is then repeatedly and/or cyclically checked in step S3whether the field of view 21 shows and/or contains the object, ornavigation instruction 22, positioned at the part of the environment MK.This can be achieved by comparing the coordinates for the field of view21 and the navigation instruction 22 in the global coordinate system 16.At this point, it should be taken into account that both the field ofview 21 and the navigation instruction 22 can be two dimensional, andaccordingly include, or be assigned, a two-dimensional collection of, ortwo dimensionally distributed, coordinates. If, for example, all of thecoordinates for the navigation instruction are contained in the field ofview 21, the navigation instruction 22 can be displayed entirely in thefield of view 21.

If it is determined in step S3 that the navigation instruction 22 isentirely contained in the field of view 21 (arrow Y in FIG. 1 a ), anormal display mode is activated in step S4. The HUD 20 is then operatedin the conventional manner and in accordance with augmented reality HUDsthat can be obtained commercially, and the navigation instruction 22 isdisplayed at the position in the field of view 21 corresponding to thecenter MK of the intersection.

If instead, it is determined in step S3 that the navigation instruction22 (when positioned at or assigned to the center MK of the intersection)is not entirely within the field of view 21, an alternative display modeis activated in step S5. At this point, an alternative display of thevisual content to the normal display mode in step S4 takes place that isvisible to the driver (such that a display other than that in the normaldisplay mode is generated). Examples of this shall be specified below.It should be understood here that when one of the display modes in stepsS4 and S5 has been established, it is preferably checked at regularintervals whether this is still valid. It is therefore possible toreturn to step S3 in regular intervals (e.g., after a predetermined timeperiod has elapsed), and it is possible to check whether or not thisdetermination remains valid. It is possible in this manner to changeautomatically to the currently appropriate display mode.

Exemplary displays in the field of view 21 in the alternative displaymode shall be explained below in reference to FIGS. 2 to 4 . These viewseach correspond to the perspective of the driver through the windshieldof the vehicle 10 as it approaches the intersection 14 in FIG. 1 . Theseviews also each contain a field of view 21 for the HUD 20, in which itis possible to display virtual objects.

Both the intersection 14 and the center MK of the intersection can beseen in the example of FIG. 2 . The object, or navigation instruction 22is also shown therein, which cannot be seen by the driver, and is onlyshown for illustrating purposes. The two-dimensional field of view 21can also be seen. It is clear that the navigation instruction 22 at itsactual assigned position in the global coordinate system 16 (see FIG. 1) in the center MK of the intersection does not lie in the field of view21. Instead, it lies above the field of view 21 from the perspective ofthe vehicle coordinate system 18. Optionally, this relative position isdetermined in a separate step (e.g., within the alternative displaymode), e.g., that the object in its state assigned to the part of theenvironment lies above or below (as described below in reference to FIG.3 ), the field of view 21. Accordingly, the object 24 (the alternativeobject 24 below) is then also displayed in the field of view 21 based onthis relative position. In this example, this is shown such that thealternative object 24 is displayed at the upper edge or upper border ofthe field of view 21. In other words, the alternative object 24 istherefore shown off-center. It is displaced vertically upward above themiddle of the field of view 21, since the center MK of the virtualobject 22 that is to be displayed on the part of the environment is alsopositioned above the field of view 21.

Merely by way of example, the alternative object 24 in these cases is anobject of the same type and content as the actual object, or the actualnavigation instruction, that is to be displayed.

FIG. 3 shows an example in which the field of view 21 lies above thecenter MK of the intersection (e.g., due to a selected driver setting),and in particular the navigation instruction 22 positioned there. Thealternative object 24 is accordingly placed at the lower edge of thefield of view 21, in acknowledgment of this optionally separatelydetermined relative position.

In general, the optional determination of the relative position can belimited to the determination of a vertical relative position, forexample, to whether the field of view 21 is positioned at leastpartially above or below the navigation instruction 22, if the latter ispositioned at the part of the environment, or center MK of theintersection.

FIG. 4 shows an example where the field of view 21 at least partiallycontains the navigation instruction 22 (when it is positioned at thecenter MK of the intersection, concealing it here). Most of thenavigation instruction 22 remains above the field of view 21 in thisillustration, although the lower part of its three arrows extends intothe field of view 21. The alternative object 24 is preferably alsodisplayed in accordance with the relative position in this case (at theupper edge of the field of view 21 here), and none of the components ofthe actual navigation instruction 22 that is to be shown are displayedat their intended position (the center MK of the intersection). Instead,the latter can first take place when the field of view 21 is movedfurther upward in relation to the navigation instruction 22, e.g., whenapproaching the center MK of the intersection. In other words, the fieldof view 21 increasingly overlaps the navigation instruction 22 as thevehicle approaches the intersection 14, and the navigation instructionmoves down into the field of view 21. As soon as it is in the field ofview 21, the normal display mode can be activated. In some examples, theinitially generated display, or view, then corresponds to that in FIG. 4, such that it coincides with the navigation instruction 22 at the upperedge of the field of view 21. From the perspective of the driver, thisresults in a smooth transition between the two display modes, that ispreferably imperceptible to the driver.

FIG. 5 shows a situation in which a navigation instruction 22 isdisplayed in its entirety at its actual intended position (the center MKof the intersection) in the field of view 21. This example correspondsto a normal display mode, in which the navigation instructions 22 iscontained entirely in the field of view 21.

This also illustrates an example in which the navigation instruction 22covers at least a predefined dimension V of the field of view 21 todefined minimum extent, or extends along this dimension to a definedminimum extent. This relates in the present case to a vertical dimensionof the field of view 21, by way of example. A corresponding verticalheight H of the navigation instruction 22 can assumed at least 50%,preferably 60% of the corresponding vertical dimension V of the field ofview 21.

If the driver continues to approach the intersection 14 in FIG. 5 , theobject or navigation instruction 22 assigned to a specific location inthe environment then remains at this location from the perspective ofthe driver, i.e. at the center MK of the intersection. Consequently, thenavigation instruction moves toward the lower edge of the field of view21, as can be seen in FIG. 6 . Because of the size ratio described abovefor the navigation instruction 22 to the field of view 21, as thevehicle continues to approach the intersection 14, and the navigationinstruction 22 moves downward, out of the field of view 21, it is notnecessary to switch directly to the alternative display mode. This canfirst take place when the navigation instruction 22 lies entirely out ofthe field of view.

Instead, those parts of the navigation instruction 22 that continue tooverlap the field of view 21, or are contained therein, can still beshown in the field of view 21. The navigation instruction 22 istherefore cut off, so to speak, as the parts extending out of the fieldof view are not shown separately. This is shown in FIG. 7 . Because ofthe size ratio explained above, the navigation instruction 22 can stillbe seen clearly by the driver at this point.

The situation shown in FIG. 7 can also occur when the vehicle 10 movesvertically in relation to the road surface in FIG. 6 , e.g., whenpassing over a bump or depression (such as a vertical obstacle). Thesetypes of vertical movement are normally abrupt, usually in the form ofsubsiding vibrations. The field of view 21 then teeters up and down witha dampened amplitude in relation to the roadway 12, moving up and downin relation thereto. Starting with the normal display mode in FIG. 6 ,in particular when the size ratio described above is satisfied, butpreferably independently thereof, the display is not immediately changedto the alternative display mode due to the temporary motion of the fieldof view 21 in relation to the roadway 12, and thus also to the center MKof the intersection. Instead, at least partially cut-off views can begenerated, as shown in FIG. 7 , even with navigation instructions thatdo not satisfy the size ratio described above, when the field of view 21is moved abruptly up or down, starting from the position shown in FIG. 6(see the corresponding state shown in FIG. 7 ). The recognition of thetemporary character of a corresponding relative motion of the field ofview 21 in relation to the environment, and in particular to the centerMK of the intersection, can take place with acceleration sensors 19 (seeFIG. 1 ) for a suspension system in the vehicle 10 in particular.

FIG. 8 shows a display that may occur when the alternative display modeis activated and the temporary relative motion of the field of view tothe environment described above takes place, in particular due to avertical movement of the vehicle 10. In this case, the initial situationcan correspond to that in FIG. 2 , e.g., with a flat road surface 12.Starting from this situation, if the vehicle passes over a depression,the field of view 21 may slip downward in relation to the environment,and in particular the center MK of the intersection.

Because of the temporary aspect of this relative movement, thealternative display element 24 is not moved down along with the field ofview 21, in order to avoid irritating the driver. It therefore does notremain fixed in place within the field of view 21 (e.g., fixed in placein relation to a center of the field of view 21, which is notspecifically indicated in the drawing). Instead, it preferably remainsfixed in place in relation to the environment and/or the center MK ofthe intersection. Furthermore, preferably only that part of thealternative display element 24 is displayed that still overlaps thefield of view 21. In this case, this is the lower part of the threearrows (e.g., in comparison to the illustration in FIG. 2 ).

When the field of view 21 moves back up as the vehicle 10 returns to itsnormal position in FIG. 8 , the alternative display element 24 can bemoved back down in the field of view 21. The alternative object 24 canreassume its fixed position in the field of view 21 once it fullyreturns to the field of view 21 and/or the vertical movement has abated,or the field of view 21 has returned to the original relative positionto the environment. It then no longer has a fixed relationship to thecenter MK of the intersection, and can therefore move in relationthereto.

LIST OF REFERENCE SYMBOLS

-   -   10 vehicle    -   12 roadway    -   14 intersection    -   16 global (environment) coordinate system    -   18 vehicle coordinate system    -   19 acceleration sensor    -   20 head-up display (HUD)    -   21 field of view    -   22 virtual object (navigation instruction)    -   24 virtual display in alternative display mode (alternative        object)    -   MK part of environment (center of intersection)    -   B direction of movement of the vehicle    -   H vertical height of the object    -   V vertical dimension of the field of view

The invention claimed is:
 1. A method for operating a head-up display for a vehicle, comprising: obtaining an assignment of at least one virtual object that can be displayed to a part of a display environment; activating a first display mode for the head-up display when the virtual object assigned to the part of the display environment is within a field of view for the head-up display; activating an alternate display mode for the head-up display when the object assigned to the part of the environment is at least partially not contained within the field of view for the head-up display, wherein the alternative display mode comprises generating a virtual display; and detecting a temporary change in the position of the field of view relative to the display environment, and moving the virtual display relative to the field of view.
 2. The method of claim 1, wherein activating the alternative display mode comprises activating the alternative display mode based on a type and/or content of the virtual object.
 3. The method of claim 1, wherein activating the alternative display mode comprises activating the alternative display mode based on a relative position of the virtual object assigned to the part of the display environment and the field of view.
 4. The method of claim 1, wherein activating the alternative display mode comprises offsetting the display environment relative to a center of the field of view, based on a relative position of the object to the field of view.
 5. The method of claim 1, wherein activating the alternative display mode comprises generating the display environment in or near an edge of the field of view.
 6. The method of claim 1, further comprising at least partially displaying the at least one virtual object when the at least one virtual object overlaps a dimension of the field of view and is not entirely within the field of view.
 7. The method of claim 1, further comprising, after activating the first display mode: detecting a temporary change in the relative position of the field of view of the display environment; detecting that the virtual object temporarily and at least partially exits the field of view; and maintaining activation of the first display mode, and not activating the alternate display mode.
 8. The method of claim 1, further comprising scaling a size of the virtual object assigned to the part of the display environment.
 9. The method of claim 1, wherein detecting the temporary change comprises detecting a relative position of the vehicle based on values from at least one acceleration sensor.
 10. A system for a vehicle, comprising: a heads-up display; and a processing apparatus, operatively coupled to the heads-up display, wherein the heads-up display and processing apparatus are configured to obtain an assignment of at least one virtual object that can be displayed to a part of a display environment; activate a first display mode for the head-up display when the virtual object assigned to the part of the display environment is within a field of view for the head-up display; activate an alternate display mode for the head-up display when the object assigned to the part of the environment is at least partially not contained within the field of view for the head-up display, wherein the alternative display mode comprises generating a virtual display; and detect a temporary change in the position of the field of view relative to the display environment, and move the virtual display relative to the field of view.
 11. The system of claim 10, wherein the heads-up display and processing apparatus are configured to activate the alternative display mode by activating the alternative display mode based on a type and/or content of the virtual object.
 12. The system of claim 10, wherein the heads-up display and processing apparatus are configured to activate the alternative display mode by activating the alternative display mode based on a relative position of the virtual object assigned to the part of the environment and the field of view.
 13. The system of claim 10, wherein the heads-up display and processing apparatus are configured to activate the alternative display mode by offsetting the display environment relative to a center of the field of view, based on a relative position of the object to the field of view.
 14. The system of claim 10, wherein the heads-up display and processing apparatus are configured to activate the alternative display mode by generating the display environment in or near an edge of the field of view.
 15. The system of claim 10, wherein the heads-up display and processing apparatus are configured to at least partially display the at least one virtual object when the at least one virtual object overlaps a dimension of the field of view and is not entirely within the field of view.
 16. The system of claim 10, wherein the heads-up display and processing apparatus are configured to, after activating the first display mode: detect a temporary change in the relative position of the field of view of the display environment; detect that the virtual object temporarily and at least partially exits the field of view; and maintain activation of the first display mode, and not activating the alternate display mode.
 17. The system of claim 10, further comprising sealing a size of the virtual object assigned to the part of the display environment.
 18. The system of claim 10, further comprising at least one acceleration sensor, operatively coupled to the processing apparatus, wherein the processing apparatus is configured to detect the temporary change by detecting a relative position of the vehicle based on values from the at least one acceleration sensor.
 19. A method for operating a head-up display for a vehicle, comprising: obtaining an assignment of at least one virtual object that can be displayed to a part of a display environment; activating a first display mode for the head-up display when the virtual object assigned to the part of the display environment is within a field of view for the head-up display; activating an alternate display mode for the head-up display when the object assigned to the part of the environment is at least partially not contained within the field of view for the head-up display, wherein the alternative display mode comprises generating a virtual display; and detecting a temporary change in the position of the field of view relative to the display environment, and moving the virtual display relative to the field of view, wherein activating the alternative display mode comprises one of (i) activating the alternative display mode based on a type and/or content of the virtual object, (ii) activating the alternative display mode based on a relative position of the virtual object assigned to the part of the display environment and the field of view, and (iii) offsetting the display environment relative to a center of the field of view, based on a relative position of the object to the field of view. 